1. Field of the Invention:
This invention relates to a method of essentially preventing the formation of 3-mercapto-4-methyl-2-pentanone by controlling an ammonium thiocyanate-methyl isobutyl ketone regeneration process. 3-Mercapto-4-methyl-2-pentanone is an offensive compound which can be normally produced in the zirconium/hafnium separation process if the ketone regeneration process is not carefully controlled.
2. Description of the Prior Art:
In view of the recent emphasis placed on environmental control and pollution, it has become increasingly important to reduce all forms of offensive effluents from chemical processing plants. In the separation of hafnium from zirconium, ammonium thiocyanate is used as a complexing agent for the liquid-liquid extraction process. During various steps of the operation, the thiocyanate can enter into side reactions, which can produce offensive sulphur containing compounds. Large expenditures have been set forth to determine what these compounds are and how to remove them or prevent their production. Until the present, these procedures have not been fully successful, mostly due to the difficulty in determining the precise identity of these compounds, and in the difficulty in removing these compounds from the effluent to a degree where they are not detectable by humans. Instruments for detecting the presence of these compounds are extremely precise and refined; however, they have still not reached the sensitivity of the human nose, which can pick up such minute amounts of 3-mercapto-4-methyl-2-pentanone as one part in 10 billion.
In view of this fact, it has become increasingly important to determine exactly what the offensive compound is and to find a way to prevent its formation, rather than remove the compound, since detection of the efficiency of removal is not sophisticated enough.